An Electrical Method of Counting the Number of Alpha-Particles from Radio-active Substances; The Charge and Nature of the Alpha Particle; On a Diffuse Reflection of the Alpha Particles; et al.(117 views)
Description: FIRST PRINTINGS of papers by Rutherford, Geiger, and Marsden reporting the results of the famous experiments on alpha particle scattering- the basis for the discovery of the atomic nucleus and Rutherford’s model of the atom; also describing and documenting the invention and use of what would become known as the “Geiger counter” to detect atomic particles. ?In 1907 Rutherford was translated to the chair of physics in the University of Manchester. Here he found a young graduate of Erlangen, Hans Geiger, with whom he devised (Proc. R.S., 81, pp141, 162) an electrical method of counting the alpha-particles directly, the Geiger counter as it has since been generally called... This counting of atoms one by one was a great achievement... ?In the work of Rutherford and Geiger on counting alpha particles by the electric method, carried out in 1908, some of the difficulties that had to be overcome were due to the scattering of alpha rays in passing through matter. Geiger made a special study of the scattering for small angles of deflection, and in 1909 Rutherford suggested to one of his research students, E. Marsden, an examination of the possibility of scattering through large angles. As a result of this suggestion, experiments were carried out by Geiger and Marsden, which showed (Proc. R.S., 82, pp.495) that alpha particles fired at a thin plate of matter can be scattered inside the material to such an extent that some of them emerge again on the side of the plate at which they entered: and calculation showed that some of the alpha particles must have been deflected at single encounters through angles greater than a right angle? (Whittaker, pp.7,20). Rutherford later explained his reaction to this startling discovery: "It was quite the most incredible event that has ever happened to me in my life. It was almost as incredible as if you fired a 15-inch shell at a piece of tissue paper and it came back and hit you. On consideration I realised that this scattering backwards must be the result of a single collision, and when I made calculations I saw that it was impossible to get anything of that order of magnitude unless you took a system in which the greatest part of the mass of the atom was concentrated in a minute nucleus." Rutherford used the results of Geiger and Marsden?s experiments to form the basis for his classic paper announcing the discovery of the atomic nucleus and his model of the atom. Geiger and Rutherford: An Electrical Method of Counting the Number of Alpha-Particles from Radio-active Substances, Proc. R.S., vol 81, pp. 141-61, 1908; The Charge and Nature of the Alpha Particle; ibid., pp. 162-73; Geiger and Marsden: On a Diffuse Reflection of the Alpha Particles, Proc. R.S., vol 82, pp. 495-500, 1909; Geiger: The Scattering of Alpha Particles by Matter, Proc. R.S. vol 83, pp. 492-504, 1909; Geiger: The Ionisation Produced by an Alpha Particle, Proc. R.S., vol 81, pp. 486-95, 1908 (part I); vol 83, pp.505-15, 1910 (part II). Vol. 81 & 82 bound in library cloth. Cancel stamps from Queens College, Oxford; light rubbing with remnants of library marks to foot of spine. Vol 83, fine in original wrappers.
Artist or Maker: GEIGER, HANS; Rutherford, Ernest; MARSDEN, ERNEST